The Fifth Circuit Court of Appeals has ruled in favor of BP Exploration and Production, affirming a lower court's decision to grant summary judgment in a case involving a plaintiff who claimed his prostate cancer was caused by exposure to crude oil during the 2010 Deepwater Horizon oil spill cleanup. The ruling, issued on May 27, 2026, affects Floyd Ruffin, the plaintiff, who alleged that his exposure to toxic chemicals during his work led to his cancer diagnosis. This case is significant as it addresses the standards for expert testimony in toxic tort cases, which are crucial for establishing causation in such claims.
Floyd Ruffin worked as a shoreline cleanup worker in Louisiana for five months following the catastrophic oil spill in 2010. Five years later, he was diagnosed with prostate cancer and subsequently sued BP under the Deepwater Horizon medical benefits class action settlement, claiming that his exposure to harmful chemicals during the cleanup caused his illness. The case was filed in the Eastern District of Louisiana and later appealed to the Fifth Circuit.
The dispute centers on whether Ruffin's expert testimony was sufficient to establish causation between his alleged exposure to crude oil and his cancer. BP argued that the expert testimony presented by Ruffin did not meet the necessary standards of relevance and reliability as required under Federal Rule of Evidence 702 and the landmark Supreme Court case Daubert v. Merrell Dow Pharmaceuticals, Inc. The district court had previously excluded Ruffin's expert testimony, leading to the summary judgment in favor of BP.
In its ruling, the Fifth Circuit agreed with the district court's decision to exclude Ruffin's expert testimony, which was provided by Dr. Benjamin Rybicki, a genetic and molecular epidemiologist. The court noted that Rybicki's testimony suffered from significant analytical flaws. Specifically, the court stated, "Rybicki’s testimony is inadmissible because it neither ‘identif[ied] the harmful level of exposure to a chemical’ necessary to cause prostate cancer nor proved that Ruffin was ‘exposed to’ that harmful level." This ruling underscores the importance of presenting scientifically valid and reliable evidence in toxic tort cases.
Ruffin's case was evaluated under the standards set forth in Daubert, which requires that expert testimony be both relevant and reliable. The Fifth Circuit explained that to establish a defendant's liability in a toxic tort case, a plaintiff must demonstrate causation, which includes both general causation (whether a substance can cause a particular injury in the general population) and specific causation (whether the substance caused the plaintiff's specific injury). The court found that Rybicki's testimony did not adequately establish general causation, as it failed to demonstrate that the chemicals Ruffin was exposed to were capable of causing prostate cancer.
The court highlighted several shortcomings in Rybicki's analysis. Although he reported that polycyclic aromatic hydrocarbons (PAHs) are capable of causing prostate cancer, he did not identify a specific level of exposure that would lead to the disease. The court noted that Rybicki's testimony was limited, primarily focusing on one specific PAH, benzo(a)pyrene, which he acknowledged was not conclusively shown to cause prostate cancer. As a result, the court concluded that there was an "analytical gap" between Rybicki's data and the conclusions he sought to draw.
This ruling may have broader implications for similar toxic tort cases, particularly those related to the Deepwater Horizon oil spill. The court's decision reinforces the need for plaintiffs to provide robust scientific evidence linking their injuries to specific exposures. It also clarifies the standards for expert testimony, emphasizing that simply demonstrating a potential link between exposure and disease is not enough without sufficient scientific backing.
Looking forward, Ruffin's options for appeal appear limited. The Fifth Circuit's ruling is a significant affirmation of the lower court's decisions, and it is unclear if there are grounds for further appeal. As of now, there are no related cases pending in the Fifth Circuit that would directly affect this ruling.